Please help completing this slider code I am stuck.

Please help completing this slider code I am stuck.

Hello,

I am makeing this neat slider. You click the links and the slider comes out but when I click the same link twice it comes back. I need to not have it move when it is clicked twice. For a better I dea of what I need Take a look at my code: and here is a site that has the effect that I want in flash(I know this is j query and not flash this is just an example:http://artistecard.com/JBoog


<script>
$(function () {
var current


$("#aOne").click(function () {
              trade($("#div1"));
             
});
$("#aTwo").click(function () {
              trade($("#div2"));
});
$("#aThree").click(function () {
              trade($("#div3"));
});
var trade = function (el) {
            $(".current").animate({ left: -400 }, 2000, "linear",
                    function () {
                              $(this).css("left", "4000px").removeClass("current");
                  });
            el.addClass("current");
                  el.animate({
                          left: 150
                      }, 1000);
                  }
            });
</script>
</head>

<body>

<div><a id="aOne" href="#">Div One</a><a id="aTwo" href="#">Div Two</a><a id="aThree"       href="#">Div Three</a></div>
<div class="slider"
       style="position:absolute;width:150px;height:150px; top:150px;left:4000px;background-      color:#EEE;" id="div1" >
                  First Div
</div>
<div class="slider"
      style="position:absolute;width:150px;height:150px; top:150px;left:4000px;background-            color:#AAA" id="div2" >
                    Second Div
</div>
<div class="slider"
              style="position:absolute;width:150px;height:150px; top:150px;left:4000px;background-                  color:#555" id="div3" >
                  Third Div
</div>


</body>



Thank you.